init_waitqueue_head(&port->open_wait);
        init_waitqueue_head(&port->close_wait);
        mutex_init(&port->mutex);
+       spin_lock_init(&port->lock);
        port->close_delay = (50 * HZ) / 100;
        port->closing_wait = (3000 * HZ) / 100;
 }
 EXPORT_SYMBOL(tty_port_free_xmit_buf);
 
 
+/**
+ *     tty_port_tty_get        -       get a tty reference
+ *     @port: tty port
+ *
+ *     Return a refcount protected tty instance or NULL if the port is not
+ *     associated with a tty (eg due to close or hangup)
+ */
+
+struct tty_struct *tty_port_tty_get(struct tty_port *port)
+{
+       unsigned long flags;
+       struct tty_struct *tty;
+
+       spin_lock_irqsave(&port->lock, flags);
+       tty = tty_kref_get(port->tty);
+       spin_unlock_irqrestore(&port->lock, flags);
+       return tty;
+}
+EXPORT_SYMBOL(tty_port_tty_get);
+
+/**
+ *     tty_port_tty_set        -       set the tty of a port
+ *     @port: tty port
+ *     @tty: the tty
+ *
+ *     Associate the port and tty pair. Manages any internal refcounts.
+ *     Pass NULL to deassociate a port
+ */
+
+void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&port->lock, flags);
+       if (port->tty)
+               tty_kref_put(port->tty);
+       port->tty = tty;
+       spin_unlock_irqrestore(&port->lock, flags);
+}
+EXPORT_SYMBOL(tty_port_tty_set);
 
         * 64 bytes, to ensure I do not get throttled.
         * Ask USB mailing list for better aproach.
         */
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
 
        if (!tty) {
                schedule_work(&priv->rx_work);
        count = min(64, serial_buf_data_avail(priv->rx_buf));
 
        if (count <= 0)
-               return; /* We have finished sending everything. */
+               goto out; /* We have finished sending everything. */
 
        tty_prepare_flip_string(tty, &data, count);
        if (!data) {
-               err("%s- kzalloc(%d) failed.", __func__, count);
-               return;
+               dev_err(&port->dev, "%s- kzalloc(%d) failed.",
+                                                       __func__, count);
+               goto out;
        }
 
        serial_buf_get(priv->rx_buf, data, count);
 
        if (serial_buf_data_avail(priv->rx_buf))
                schedule_work(&priv->rx_work);
-
+out:           
+       tty_kref_put(tty);
        return;
 }
 /* End of private methods */
        usb_serial_debug_data(debug, &port->dev, __func__,
                                urb->actual_length, urb->transfer_buffer);
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                if (urb->actual_length <= 2) {
                        /* This is an incomplete package */
                }
                aircable_read(&priv->rx_work);
        }
+       tty_kref_put(tty);
 
        /* Schedule the next read _if_ we are still open */
        if (port->port.count) {
 
         * to look in to this before committing any code.
         */
        if (priv->last_lsr & BELKIN_SA_LSR_ERR) {
-               tty = port->port.tty;
+               tty = tty_port_tty_get(&port->port);
                /* Overrun Error */
                if (priv->last_lsr & BELKIN_SA_LSR_OE) {
                }
                /* Break Indicator */
                if (priv->last_lsr & BELKIN_SA_LSR_BI) {
                }
+               tty_kref_put(tty);
        }
 #endif
        spin_unlock_irqrestore(&priv->lock, flags);
 
        }
 
        port = serial->port[0];
-       port->port.tty = NULL;
+       tty_port_tty_set(&port->port, NULL);
 
        info->port = port;
 
                        }
                        memset(&dummy, 0, sizeof(struct ktermios));
                        tty->termios = termios;
-                       port->port.tty = tty;
+                       tty_port_tty_set(&port->port, tty);
                }
 
                /* only call the device specific open if this
                        tty_termios_encode_baud_rate(termios, baud, baud);
                        serial->type->set_termios(tty, port, &dummy);
 
-                       port->port.tty = NULL;
+                       tty_port_tty_set(&port->port, NULL);
                        kfree(termios);
                        kfree(tty);
                }
        return retval;
 free_termios:
        kfree(termios);
-       port->port.tty = NULL;
+       tty_port_tty_set(&port->port, NULL);
 free_tty:
        kfree(tty);
 reset_open_count:
 
                return;
        }
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (!tty) {
                dbg("%s - ignoring since device not open\n", __func__);
                return;
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        spin_lock(&priv->lock);
 
 
        }
        spin_unlock_irqrestore(&priv->lock, flags);
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (!tty) {
                dbg("%s - bad tty pointer - exiting", __func__);
                return;
                                        data[i]);
                        tty_insert_flip_char(tty, data[i], tty_flag);
                }
-               tty_flip_buffer_push(port->port.tty);
+               tty_flip_buffer_push(tty);
        }
 
        spin_lock_irqsave(&priv->lock, flags);
        spin_unlock_irqrestore(&priv->lock, flags);
 
 continue_read:
+       tty_kref_put(tty);
 
        /* Continue trying to always read... unless the port has closed. */
 
 
 
 static void digi_wakeup_write(struct usb_serial_port *port)
 {
-       tty_wakeup(port->port.tty);
+       struct tty_struct *tty = tty_port_tty_get(&port->port);
+       tty_wakeup(tty);
+       tty_kref_put(tty);
 }
 
 
 {
 
        struct usb_serial_port *port = urb->context;
-       struct tty_struct *tty = port->port.tty;
+       struct tty_struct *tty;
        struct digi_port *priv = usb_get_serial_port_data(port);
        int opcode = ((unsigned char *)urb->transfer_buffer)[0];
        int len = ((unsigned char *)urb->transfer_buffer)[1];
                return -1;
        }
 
+       tty = tty_port_tty_get(&port->port);
        spin_lock(&priv->dp_port_lock);
 
        /* check for throttle; if set, do not resubmit read urb */
                }
        }
        spin_unlock(&priv->dp_port_lock);
+       tty_kref_put(tty);
 
        if (opcode == DIGI_CMD_RECEIVE_DISABLE)
                dbg("%s: got RECEIVE_DISABLE", __func__);
 
        struct usb_serial_port *port = urb->context;
        struct usb_serial *serial = port->serial;
+       struct tty_struct *tty;
        struct digi_port *priv = usb_get_serial_port_data(port);
        int opcode, line, status, val;
        int i;
                if (priv == NULL)
                        return -1;
 
+               tty = tty_port_tty_get(&port->port);
                rts = 0;
                if (port->port.count)
-                       rts = port->port.tty->termios->c_cflag & CRTSCTS;
-
+                       rts = tty->termios->c_cflag & CRTSCTS;
+               
                if (opcode == DIGI_CMD_READ_INPUT_SIGNALS) {
                        spin_lock(&priv->dp_port_lock);
                        /* convert from digi flags to termiox flags */
                                priv->dp_modem_signals |= TIOCM_CTS;
                                /* port must be open to use tty struct */
                                if (rts) {
-                                       port->port.tty->hw_stopped = 0;
+                                       tty->hw_stopped = 0;
                                        digi_wakeup_write(port);
                                }
                        } else {
                                priv->dp_modem_signals &= ~TIOCM_CTS;
                                /* port must be open to use tty struct */
                                if (rts)
-                                       port->port.tty->hw_stopped = 1;
+                                       tty->hw_stopped = 1;
                        }
                        if (val & DIGI_READ_INPUT_SIGNALS_DSR)
                                priv->dp_modem_signals |= TIOCM_DSR;
                } else if (opcode == DIGI_CMD_IFLUSH_FIFO) {
                        wake_up_interruptible(&priv->dp_flush_wait);
                }
+               tty_kref_put(tty);
        }
        return 0;
 
 
  *     Moved MOD_DEC_USE_COUNT to end of empeg_close().
  *
  * (12/03/2000) gb
- *     Added port->port.tty->ldisc.set_termios(port->port.tty, NULL) to
- *     empeg_open(). This notifies the tty driver that the termios have
- *     changed.
+ *     Added tty->ldisc.set_termios(port, tty, NULL) to empeg_open().
+ *     This notifies the tty driver that the termios have changed.
  *
  * (11/13/2000) gb
  *     Moved tty->low_latency = 1 from empeg_read_bulk_callback() to
 
        usb_serial_debug_data(debug, &port->dev, __func__,
                                                urb->actual_length, data);
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
 
        if (urb->actual_length) {
                tty_buffer_request_room(tty, urb->actual_length);
                tty_flip_buffer_push(tty);
                bytes_in += urb->actual_length;
        }
+       tty_kref_put(tty);
 
        /* Continue trying to always read  */
        usb_fill_bulk_urb(
 
        if (port->port.count <= 0)
                return;
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (!tty) {
                dbg("%s - bad tty pointer - exiting", __func__);
                return;
        priv = usb_get_serial_port_data(port);
        if (!priv) {
                dbg("%s - bad port private data pointer - exiting", __func__);
-               return;
+               goto out;
        }
 
        if (urb != port->read_urb)
                /* This will happen at close every time so it is a dbg not an
                   err */
                dbg("(this is ok on close) nonzero read bulk status received: %d", status);
-               return;
+               goto out;
        }
 
        /* count data bytes, but not status bytes */
        spin_unlock_irqrestore(&priv->rx_lock, flags);
 
        ftdi_process_read(&priv->rx_work.work);
-
+out:
+       tty_kref_put(tty);
 } /* ftdi_read_bulk_callback */
 
 
        if (port->port.count <= 0)
                return;
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (!tty) {
                dbg("%s - bad tty pointer - exiting", __func__);
                return;
        priv = usb_get_serial_port_data(port);
        if (!priv) {
                dbg("%s - bad port private data pointer - exiting", __func__);
-               return;
+               goto out;
        }
 
        urb = port->read_urb;
        if (!urb) {
                dbg("%s - bad read_urb pointer - exiting", __func__);
-               return;
+               goto out;
        }
 
        data = urb->transfer_buffer;
                        schedule_delayed_work(&priv->rx_work, 1);
                else
                        dbg("%s - port is closed", __func__);
-               return;
+               goto out;
        }
 
        /* urb is completely processed */
                        err("%s - failed resubmitting read urb, error %d",
                                                        __func__, result);
        }
+out:
+       tty_kref_put(tty);
 } /* ftdi_process_read */
 
 
 
 static void send_to_tty(struct usb_serial_port *port,
                        char *data, unsigned int actual_length)
 {
-       struct tty_struct *tty = port->port.tty;
+       struct tty_struct *tty = tty_port_tty_get(&port->port);
 
        if (tty && actual_length) {
 
                tty_insert_flip_string(tty, data, actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 }
 
 
 
 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 {
        struct urb *urb = port->read_urb;
-       struct tty_struct *tty = port->port.tty;
+       struct tty_struct *tty = tty_port_tty_get(&port->port);
        int room;
 
        /* Push data to tty */
                        tty_flip_buffer_push(tty);
                }
        }
+       tty_kref_put(tty);
 
        resubmit_read_urb(port, GFP_ATOMIC);
 }
 
        struct edgeport_serial  *edge_serial = urb->context;
        struct edgeport_port *edge_port;
        struct usb_serial_port *port;
+       struct tty_struct *tty;
        unsigned char *data = urb->transfer_buffer;
        int length = urb->actual_length;
        int bytes_avail;
 
                                        /* tell the tty driver that something
                                           has changed */
-                                       if (edge_port->port->port.tty)
-                                               tty_wakeup(edge_port->port->port.tty);
-
+                                       tty = tty_port_tty_get(
+                                               &edge_port->port->port);
+                                       if (tty) {
+                                               tty_wakeup(tty);
+                                               tty_kref_put(tty);
+                                       }
                                        /* Since we have more credit, check
                                           if more data can be sent */
                                        send_more_port_data(edge_serial,
                    __func__, status);
        }
 
-       tty = edge_port->port->port.tty;
+       tty = tty_port_tty_get(&edge_port->port->port);
 
        if (tty && edge_port->open) {
                /* let the tty driver wakeup if it has a special
                   write_wakeup function */
                tty_wakeup(tty);
        }
+       tty_kref_put(tty);
 
        /* Release the Write URB */
        edge_port->write_in_progress = false;
        }
 
        /* Get pointer to tty */
-       tty = edge_port->port->port.tty;
+       tty = tty_port_tty_get(&edge_port->port->port);
 
        /* tell the tty driver that something has changed */
        if (tty && edge_port->open)
                tty_wakeup(tty);
+       tty_kref_put(tty);
 
        /* we have completed the command */
        edge_port->commandPending = false;
                                                        edge_serial->rxPort];
                                edge_port = usb_get_serial_port_data(port);
                                if (edge_port->open) {
-                                       tty = edge_port->port->port.tty;
+                                       tty = tty_port_tty_get(
+                                               &edge_port->port->port);
                                        if (tty) {
                                                dbg("%s - Sending %d bytes to TTY for port %d",
                                                        __func__, rxLen, edge_serial->rxPort);
                                                edge_tty_recv(&edge_serial->serial->dev->dev, tty, buffer, rxLen);
+                                               tty_kref_put(tty);
                                        }
                                        edge_port->icount.rx += rxLen;
                                }
 {
        struct usb_serial_port *port;
        struct edgeport_port *edge_port;
+       struct tty_struct *tty;
        __u8 code = edge_serial->rxStatusCode;
 
        /* switch the port pointer to the one being currently talked about */
 
                /* send the current line settings to the port so we are
                   in sync with any further termios calls */
-               /* FIXME: locking on tty */
-               if (edge_port->port->port.tty)
-                       change_port_settings(edge_port->port->port.tty,
-                               edge_port, edge_port->port->port.tty->termios);
+               tty = tty_port_tty_get(&edge_port->port->port);
+               if (tty) {
+                       change_port_settings(tty,
+                               edge_port, tty->termios);
+                       tty_kref_put(tty);
+               }
 
                /* we have completed the open */
                edge_port->openPending = false;
        }
 
        /* Place LSR data byte into Rx buffer */
-       if (lsrData && edge_port->port->port.tty)
-               edge_tty_recv(&edge_port->port->dev,
-                                       edge_port->port->port.tty, &data, 1);
-
+       if (lsrData) {
+               struct tty_struct *tty =
+                               tty_port_tty_get(&edge_port->port->port);
+               if (tty) {
+                       edge_tty_recv(&edge_port->port->dev, tty, &data, 1);
+                       tty_kref_put(tty);
+               }
+       }
        /* update input line counters */
        icount = &edge_port->icount;
        if (newLsr & LSR_BREAK)
 
                                                                int flush)
 {
        int baud_rate;
-       struct tty_struct *tty = port->port->port.tty;
+       struct tty_struct *tty = tty_port_tty_get(&port->port->port);
        wait_queue_t wait;
        unsigned long flags;
 
        if (flush)
                edge_buf_clear(port->ep_out_buf);
        spin_unlock_irqrestore(&port->ep_lock, flags);
+       tty_kref_put(tty);
 
        /* wait for data to drain from the device */
        timeout += jiffies;
        /* Save the new modem status */
        edge_port->shadow_msr = msr & 0xf0;
 
-       tty = edge_port->port->port.tty;
+       tty = tty_port_tty_get(&edge_port->port->port);
        /* handle CTS flow control */
        if (tty && C_CRTSCTS(tty)) {
                if (msr & EDGEPORT_MSR_CTS) {
                        tty->hw_stopped = 1;
                }
        }
+       tty_kref_put(tty);
 
        return;
 }
        struct async_icount *icount;
        __u8 new_lsr = (__u8)(lsr & (__u8)(LSR_OVER_ERR | LSR_PAR_ERR |
                                                LSR_FRM_ERR | LSR_BREAK));
+       struct tty_struct *tty;
 
        dbg("%s - %02x", __func__, new_lsr);
 
                new_lsr &= (__u8)(LSR_OVER_ERR | LSR_BREAK);
 
        /* Place LSR data byte into Rx buffer */
-       if (lsr_data && edge_port->port->port.tty)
-               edge_tty_recv(&edge_port->port->dev, edge_port->port->port.tty, &data, 1);
+       if (lsr_data) {
+               tty = tty_port_tty_get(&edge_port->port->port);
+               if (tty) {
+                       edge_tty_recv(&edge_port->port->dev, tty, &data, 1);
+                       tty_kref_put(tty);
+               }
+       }
 
        /* update input line counters */
        icount = &edge_port->icount;
                ++data;
        }
 
-       tty = edge_port->port->port.tty;
+       tty = tty_port_tty_get(&edge_port->port->port);
        if (tty && urb->actual_length) {
                usb_serial_debug_data(debug, &edge_port->port->dev,
                                        __func__, urb->actual_length, data);
                                                        urb->actual_length);
                edge_port->icount.rx += urb->actual_length;
        }
+       tty_kref_put(tty);
 
 exit:
        /* continue read unless stopped */
        struct usb_serial_port *port = urb->context;
        struct edgeport_port *edge_port = usb_get_serial_port_data(port);
        int status = urb->status;
+       struct tty_struct *tty;
 
        dbg("%s - port %d", __func__, port->number);
 
        }
 
        /* send any buffered data */
-       edge_send(port->port.tty);
+       tty = tty_port_tty_get(&port->port);
+       edge_send(tty);
+       tty_kref_put(tty);
 }
 
 static int edge_open(struct tty_struct *tty,
 
        /* set up the port settings */
        if (tty)
-               edge_set_termios(tty, port, port->port.tty->termios);
+               edge_set_termios(tty, port, tty->termios);
 
        /* open up the port */
 
 
        usb_serial_debug_data(debug, &port->dev, __func__,
                                                urb->actual_length, data);
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                tty_buffer_request_room(tty, urb->actual_length);
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
                bytes_in += urb->actual_length;
        }
+       tty_kref_put(tty);
 
        /* Continue trying to always read  */
        usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 
        usb_serial_debug_data(debug, &port->dev, __func__,
                                        urb->actual_length, data);
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                tty_buffer_request_room(tty, urb->actual_length);
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        /* Continue trying to always read  */
        usb_fill_bulk_urb(port->read_urb, port->serial->dev,
 
                        ir_baud = *data & 0x0f;
                usb_serial_debug_data(debug, &port->dev, __func__,
                                                urb->actual_length, data);
-               tty = port->port.tty;
+               tty = tty_port_tty_get(&port->port);
                if (tty_buffer_request_room(tty, urb->actual_length - 1)) {
                        tty_insert_flip_string(tty, data+1, urb->actual_length - 1);
                        tty_flip_buffer_push(tty);
                }
+               tty_kref_put(tty);
 
                /*
                 * No break here.
 
        }
 
        dbg("%s - %i chars to write", __func__, urb->actual_length);
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (data == NULL)
                dbg("%s - data is NULL !!!", __func__);
        if (tty && urb->actual_length && data) {
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
        iuu_led_activity_on(urb);
 }
 
 
        }
 
        port =  urb->context;
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                /* 0x80 bit is error flag */
                if ((data[0] & 0x80) == 0) {
                }
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        /* Resubmit urb so we continue receiving */
        urb->dev = port->serial->dev;
        struct usb_serial                       *serial;
        struct usb_serial_port                  *port;
        struct keyspan_port_private             *p_priv;
+       struct tty_struct                       *tty;
        int old_dcd_state, err;
        int status = urb->status;
 
        p_priv->dcd_state = ((msg->gpia_dcd) ? 1 : 0);
        p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-       if (port->port.tty && !C_CLOCAL(port->port.tty)
-           && old_dcd_state != p_priv->dcd_state) {
-               if (old_dcd_state)
-                       tty_hangup(port->port.tty);
-               /*  else */
-               /*      wake_up_interruptible(&p_priv->open_wait); */
+       if (old_dcd_state != p_priv->dcd_state) {
+               tty = tty_port_tty_get(&port->port);
+               if (tty && !C_CLOCAL(tty))
+                       tty_hangup(tty);
+               tty_kref_put(tty);
        }
 
        /* Resubmit urb so we continue receiving */
                p_priv = usb_get_serial_port_data(port);
                data = urb->transfer_buffer;
 
-               tty = port->port.tty;
-               if (urb->actual_length) {
+               tty =tty_port_tty_get(&port->port);
+               if (tty && urb->actual_length) {
                        tty_insert_flip_string(tty, data, urb->actual_length);
                        tty_flip_buffer_push(tty);
                }
+               tty_kref_put(tty);
 
                /* Resubmit urb so we continue receiving */
                urb->dev = port->serial->dev;
        struct usb_serial                       *serial;
        struct usb_serial_port                  *port;
        struct keyspan_port_private             *p_priv;
+       struct tty_struct                       *tty;
        int old_dcd_state;
        int status = urb->status;
 
        p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
        p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-       if (port->port.tty && !C_CLOCAL(port->port.tty)
-           && old_dcd_state != p_priv->dcd_state) {
-               if (old_dcd_state)
-                       tty_hangup(port->port.tty);
-               /*  else */
-               /*      wake_up_interruptible(&p_priv->open_wait); */
+       if( old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+               tty = tty_port_tty_get(&port->port);
+               if (tty && !C_CLOCAL(tty)) 
+                       tty_hangup(tty);
+               tty_kref_put(tty);
        }
 
                /* Resubmit urb so we continue receiving */
        p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
        p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-       if (port->port.tty && !C_CLOCAL(port->port.tty)
-           && old_dcd_state != p_priv->dcd_state) {
-               if (old_dcd_state)
-                       tty_hangup(port->port.tty);
-               /*  else */
-               /*      wake_up_interruptible(&p_priv->open_wait); */
+       if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+               struct tty_struct *tty = tty_port_tty_get(&port->port);
+               if (tty && !C_CLOCAL(tty))
+                       tty_hangup(tty);
+               tty_kref_put(tty);
        }
 
        /* Resubmit urb so we continue receiving */
        }
 
        port =  urb->context;
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                /* 0x80 bit is error flag */
                if ((data[0] & 0x80) == 0) {
                }
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        /* Resubmit urb so we continue receiving */
        urb->dev = port->serial->dev;
                                return;
                        }
                        port = serial->port[data[i++]];
-                       tty = port->port.tty;
+                       tty = tty_port_tty_get(&port->port);
                        len = data[i++];
 
                        /* 0x80 bit is error flag */
                        }
                        if (port->port.count)
                                tty_flip_buffer_push(tty);
+                       tty_kref_put(tty);
                }
        }
 
        port =  urb->context;
        p_priv = usb_get_serial_port_data(port);
 
-       tty = port->port.tty;
        if (urb->actual_length) {
+               tty = tty_port_tty_get(&port->port);
                /* if current mode is DMA, looks like usa28 format
                   otherwise looks like usa26 data format */
 
                        }
                }
                tty_flip_buffer_push(tty);
+               tty_kref_put(tty);
        }
 
        /* Resubmit urb so we continue receiving */
        struct usb_serial                       *serial;
        struct usb_serial_port                  *port;
        struct keyspan_port_private             *p_priv;
+       struct tty_struct                       *tty;
        int old_dcd_state, err;
        int status = urb->status;
 
        p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
        p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-       if (port->port.tty && !C_CLOCAL(port->port.tty)
-           && old_dcd_state != p_priv->dcd_state) {
-               if (old_dcd_state)
-                       tty_hangup(port->port.tty);
-               /*  else */
-               /*      wake_up_interruptible(&p_priv->open_wait); */
+       if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+               tty = tty_port_tty_get(&port->port);
+               if (tty && !C_CLOCAL(tty))
+                       tty_hangup(tty);
+               tty_kref_put(tty);
        }
 
        /* Resubmit urb so we continue receiving */
        p_priv->cts_state = ((msg->hskia_cts) ? 1 : 0);
        p_priv->dcd_state = ((msg->gpia_dcd) ? 1 : 0);
 
-       if (port->port.tty && !C_CLOCAL(port->port.tty)
-           && old_dcd_state != p_priv->dcd_state) {
-               if (old_dcd_state)
-                       tty_hangup(port->port.tty);
-               /*  else */
-               /*      wake_up_interruptible(&p_priv->open_wait); */
+       if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+               struct tty_struct *tty = tty_port_tty_get(&port->port);
+               if (tty && !C_CLOCAL(tty))
+                       tty_hangup(tty);
+               tty_kref_put(tty);
        }
 
        /* Resubmit urb so we continue receiving */
                        stop_urb(p_priv->out_urbs[i]);
                }
        }
-       port->port.tty = NULL;
+       tty_port_tty_set(&port->port, NULL);
 }
 
 /* download the firmware to a pre-renumeration device */
 
        struct keyspan_pda_private *priv =
                container_of(work, struct keyspan_pda_private, wakeup_work);
        struct usb_serial_port *port = priv->port;
-
-       tty_wakeup(port->port.tty);
+       struct tty_struct *tty = tty_port_tty_get(&port->port);
+       tty_wakeup(tty);
+       tty_kref_put(tty);
 }
 
 static void keyspan_pda_request_unthrottle(struct work_struct *work)
 static void keyspan_pda_rx_interrupt(struct urb *urb)
 {
        struct usb_serial_port *port = urb->context;
-       struct tty_struct *tty = port->port.tty;
+       struct tty_struct *tty = tty_port_tty_get(&port->port);
        unsigned char *data = urb->transfer_buffer;
        int retval;
        int status = urb->status;
                /* this urb is terminated, clean up */
                dbg("%s - urb shutting down with status: %d",
                    __func__, status);
-               return;
+               goto out;
        default:
                dbg("%s - nonzero urb status received: %d",
                    __func__, status);
 exit:
        retval = usb_submit_urb(urb, GFP_ATOMIC);
        if (retval)
-               err("%s - usb_submit_urb failed with result %d",
-                    __func__, retval);
+               dev_err(&port->dev,
+                       "%s - usb_submit_urb failed with result %d",
+                       __func__, retval);
+out:
+       tty_kref_put(tty);                   
 }
 
 
 
        } else {
                int bytes_sent = ((__u8 *) data)[0] +
                                 ((unsigned int) ((__u8 *) data)[1] << 8);
-               tty = port->port.tty;
+               tty = tty_port_tty_get(&port->port);
                /* we should immediately resubmit the URB, before attempting
                 * to pass the data on to the tty layer. But that needs locking
                 * against re-entry an then mixed-up data because of
                tty_buffer_request_room(tty, bytes_sent);
                tty_insert_flip_string(tty, data + 2, bytes_sent);
                tty_flip_buffer_push(tty);
+               tty_kref_put(tty);
 
                /* again lockless, but debug info only */
                priv->bytes_in += bytes_sent;
 
                return;
        }
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (urb->actual_length) {
 
                /* BEGIN DEBUG */
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
        /* someone sets the dev to 0 if the close method has been called */
        port->interrupt_in_urb->dev = port->serial->dev;
 
 
         * Work-a-round: handle the 'usual' bulk-in pipe here
         */
        if (urb->transfer_buffer_length > 2) {
-               tty = port->port.tty;
+               tty = tty_port_tty_get(&port->port);
                if (urb->actual_length) {
                        tty_insert_flip_string(tty, data, urb->actual_length);
                        tty_flip_buffer_push(tty);
+                       tty_kref_put(tty);
                }
                goto exit;
        }
         * to look in to this before committing any code.
         */
        if (priv->last_lsr & MCT_U232_LSR_ERR) {
-               tty = port->port.tty;
+               tty = tty_port_tty_get(&port->port);
                /* Overrun Error */
                if (priv->last_lsr & MCT_U232_LSR_OE) {
                }
                /* Break Indicator */
                if (priv->last_lsr & MCT_U232_LSR_BI) {
                }
+               tty_kref_put(tty);
        }
 #endif
        spin_unlock_irqrestore(&priv->lock, flags);
 
 
        data = urb->transfer_buffer;
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                tty_buffer_request_room(tty, urb->actual_length);
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        if (!port->read_urb) {
                dbg("URB KILLED !!!");
 
        dbg("Entering .........");
 
-       tty = mos7720_port->port->port.tty;
+       tty = tty_port_tty_get(&mos7720_port->port->port);
 
        if (tty && mos7720_port->open)
                tty_wakeup(tty);
+       tty_kref_put(tty);
 }
 
 /*
        return 0;
 }
 
-/*
- * get_number_bytes_avail - get number of bytes available
- *
- * Purpose: Let user call ioctl to get the count of number of bytes available.
- */
-static int get_number_bytes_avail(struct moschip_port *mos7720_port,
-                                 unsigned int __user *value)
-{
-       unsigned int result = 0;
-       struct tty_struct *tty = mos7720_port->port->port.tty;
-
-       if (!tty)
-               return -ENOIOCTLCMD;
-
-       result = tty->read_cnt;
-
-       dbg("%s(%d) = %d", __func__,  mos7720_port->port->number, result);
-       if (copy_to_user(value, &result, sizeof(int)))
-               return -EFAULT;
-
-       return -ENOIOCTLCMD;
-}
-
 static int set_modem_info(struct moschip_port *mos7720_port, unsigned int cmd,
                          unsigned int __user *value)
 {
        dbg("%s - port %d, cmd = 0x%x", __func__, port->number, cmd);
 
        switch (cmd) {
-       case TIOCINQ:
-               /* return number of bytes available */
-               dbg("%s (%d) TIOCINQ", __func__,  port->number);
-               return get_number_bytes_avail(mos7720_port,
-                                             (unsigned int __user *)arg);
-               break;
-
        case TIOCSERGETLSR:
                dbg("%s (%d) TIOCSERGETLSR", __func__,  port->number);
                return get_lsr_info(tty, mos7720_port,
 
        dbg("%s", "Entering ........... \n");
 
        if (urb->actual_length) {
-               tty = mos7840_port->port->port.tty;
+               tty = tty_port_tty_get(&mos7840_port->port->port);
                if (tty) {
                        tty_buffer_request_room(tty, urb->actual_length);
                        tty_insert_flip_string(tty, data, urb->actual_length);
                        dbg(" %s \n", data);
                        tty_flip_buffer_push(tty);
+                       tty_kref_put(tty);
                }
                mos7840_port->icount.rx += urb->actual_length;
                smp_wmb();
 
        dbg("%s \n", "Entering .........");
 
-       tty = mos7840_port->port->port.tty;
-
+       tty = tty_port_tty_get(&mos7840_port->port->port);
        if (tty && mos7840_port->open)
                tty_wakeup(tty);
+       tty_kref_put(tty);
 
 }
 
 
        usb_serial_debug_data(debug, &port->dev, __func__,
                              urb->actual_length, data);
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                tty_buffer_request_room(tty, urb->actual_length);
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
 exit:
        result = usb_submit_urb(urb, GFP_ATOMIC);
 
        dbg("%s - port %d", __func__, port->number);
 
        wport = serial->port[1];
-       wport->port.tty = tty;          /* FIXME */
+       tty_port_tty_set(&wport->port, tty);
 
        /* Start reading from the device */
        usb_fill_bulk_urb(port->read_urb, serial->dev,
        }
 
        if (urb->actual_length && header->oh_len) {
-               tty_insert_flip_string(port->port.tty,
-                       data + OMNINET_DATAOFFSET, header->oh_len);
-               tty_flip_buffer_push(port->port.tty);
+               struct tty_struct *tty = tty_port_tty_get(&port->port);
+               tty_insert_flip_string(tty, data + OMNINET_DATAOFFSET,
+                                                       header->oh_len);
+               tty_flip_buffer_push(tty);
+               tty_kref_put(tty);
        }
 
        /* Continue trying to always read  */
 
                dbg("%s: nonzero status: %d on endpoint %02x.",
                    __func__, status, endpoint);
        } else {
-               tty = port->port.tty;
+               tty = tty_port_tty_get(&port->port);
                if (urb->actual_length) {
                        tty_buffer_request_room(tty, urb->actual_length);
                        tty_insert_flip_string(tty, data, urb->actual_length);
                        tty_flip_buffer_push(tty);
-               } else {
+               } else 
                        dbg("%s: empty read urb received", __func__);
-               }
+               tty_kref_put(tty);
 
                /* Resubmit urb so we continue receiving */
                if (port->port.count && status != -ESHUTDOWN) {
                        portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
                        portdata->ri_state = ((signals & 0x08) ? 1 : 0);
 
-                       if (port->port.tty && !C_CLOCAL(port->port.tty) &&
-                                       old_dcd_state && !portdata->dcd_state)
-                               tty_hangup(port->port.tty);
+                       if (old_dcd_state && !portdata->dcd_state) {
+                               struct tty_struct *tty =
+                                               tty_port_tty_get(&port->port);
+                               if (tty && !C_CLOCAL(tty))
+                                       tty_hangup(tty);
+                               tty_kref_put(tty);
+                       }
                } else {
                        dbg("%s: type %x req %x", __func__,
                                req_pkt->bRequestType, req_pkt->bRequest);
                for (i = 0; i < N_OUT_URB; i++)
                        usb_kill_urb(portdata->out_urbs[i]);
        }
-       port->port.tty = NULL;  /* FIXME */
+       tty_port_tty_set(&port->port, NULL);
 }
 
 /* Helper functions used by option_setup_urbs */
 
                return;
        }
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty != NULL && urb->actual_length > 0) {
                tty_insert_flip_string(tty, data, urb->actual_length);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        /* schedule the interrupt urb if we are still open */
        if (port->port.count != 0) {
 
                tty_flag = TTY_FRAME;
        dbg("%s - tty_flag = %d", __func__, tty_flag);
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                tty_buffer_request_room(tty, urb->actual_length + 1);
                /* overrun is special, not associated with a char */
                        tty_insert_flip_char(tty, data[i], tty_flag);
                tty_flip_buffer_push(tty);
        }
-
+       tty_kref_put(tty);
        /* Schedule the next read _if_ we are still open */
        if (port->port.count) {
                urb->dev = port->serial->dev;
 
        struct usb_serial_port *port =  urb->context;
        unsigned char *data = urb->transfer_buffer;
        unsigned char length = urb->actual_length;
+       struct tty_struct *tty;
        int result;
        int status = urb->status;
 
                printk("\n");
        }
 #endif
+       tty = tty_port_tty_get(&port->port);
        if (safe) {
                __u16 fcs;
                fcs = fcs_compute10(data, length, CRC10_INITFCS);
                        if (actual_length <= (length - 2)) {
                                info("%s - actual: %d", __func__,
                                                        actual_length);
-                               tty_insert_flip_string(port->port.tty,
+                               tty_insert_flip_string(tty,
                                                        data, actual_length);
-                               tty_flip_buffer_push(port->port.tty);
+                               tty_flip_buffer_push(tty);
                        } else {
                                err("%s - inconsistent lengths %d:%d",
                                        __func__, actual_length, length);
                        err("%s - bad CRC %x", __func__, fcs);
                }
        } else {
-               tty_insert_flip_string(port->port.tty, data, length);
-               tty_flip_buffer_push(port->port.tty);
+               tty_insert_flip_string(tty, data, length);
+               tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        /* Continue trying to always read  */
        usb_fill_bulk_urb(urb, port->serial->dev,
 
                dbg("%s: nonzero status: %d on endpoint %02x.",
                    __func__, status, endpoint);
        } else {
-               tty = port->port.tty;
                if (urb->actual_length) {
+               tty = tty_port_tty_get(&port->port);
                        tty_buffer_request_room(tty, urb->actual_length);
                        tty_insert_flip_string(tty, data, urb->actual_length);
                        tty_flip_buffer_push(tty);
-               } else {
+                       tty_kref_put(tty);
+               } else
                        dbg("%s: empty read urb received", __func__);
-               }
 
                /* Resubmit urb so we continue receiving */
                if (port->port.count && status != -ESHUTDOWN) {
                        unsigned char signals = *((unsigned char *)
                                        urb->transfer_buffer +
                                        sizeof(struct usb_ctrlrequest));
+                       struct tty_struct *tty;
 
                        dbg("%s: signal x%x", __func__, signals);
 
                        portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
                        portdata->ri_state = ((signals & 0x08) ? 1 : 0);
 
-                       if (port->port.tty && !C_CLOCAL(port->port.tty) &&
+                       tty = tty_port_tty_get(&port->port);
+                       if (tty && !C_CLOCAL(tty) &&
                                        old_dcd_state && !portdata->dcd_state)
-                               tty_hangup(port->port.tty);
+                               tty_hangup(tty);
+                       tty_kref_put(tty);
                } else {
                        dbg("%s: type %x req %x", __func__,
                                req_pkt->bRequestType, req_pkt->bRequest);
        }
 
        usb_kill_urb(port->interrupt_in_urb);
-
-       port->port.tty = NULL;  /* FIXME */
+       tty_port_tty_set(&port->port, NULL);
 }
 
 static int sierra_startup(struct usb_serial *serial)
 
                tty_flag = TTY_FRAME;
        dev_dbg(&port->dev, "tty_flag = %d\n", tty_flag);
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (tty && urb->actual_length) {
                tty_buffer_request_room(tty, urb->actual_length + 1);
                /* overrun is special, not associated with a char */
                        tty_insert_flip_char(tty, data[i], tty_flag);
                tty_flip_buffer_push(tty);
        }
+       tty_kref_put(tty);
 
        /* Schedule the next read _if_ we are still open */
        if (port->port.count) {
 
 static int ti_get_lsr(struct ti_port *tport);
 static int ti_get_serial_info(struct ti_port *tport,
        struct serial_struct __user *ret_arg);
-static int ti_set_serial_info(struct ti_port *tport,
+static int ti_set_serial_info(struct tty_struct *tty, struct ti_port *tport,
        struct serial_struct __user *new_arg);
 static void ti_handle_new_msr(struct ti_port *tport, __u8 msr);
 
                                (struct serial_struct __user *)arg);
        case TIOCSSERIAL:
                dbg("%s - (%d) TIOCSSERIAL", __func__, port->number);
-               return ti_set_serial_info(tport,
-                                       (struct serial_struct __user *)arg);
+               return ti_set_serial_info(tty, tport,
+                               (struct serial_struct __user *)arg);
        case TIOCMIWAIT:
                dbg("%s - (%d) TIOCMIWAIT", __func__, port->number);
                cprev = tport->tp_icount;
        struct device *dev = &urb->dev->dev;
        int status = urb->status;
        int retval = 0;
+       struct tty_struct *tty;
 
        dbg("%s", __func__);
 
                return;
        }
 
-       if (port->port.tty && urb->actual_length) {
+       tty = tty_port_tty_get(&port->port);
+       if (tty && urb->actual_length) {
                usb_serial_debug_data(debug, dev, __func__,
                        urb->actual_length, urb->transfer_buffer);
 
                if (!tport->tp_is_open)
                        dbg("%s - port closed, dropping data", __func__);
                else
-                       ti_recv(&urb->dev->dev, port->port.tty,
+                       ti_recv(&urb->dev->dev, tty,
                                                urb->transfer_buffer,
                                                urb->actual_length);
 
                spin_lock(&tport->tp_lock);
                tport->tp_icount.rx += urb->actual_length;
                spin_unlock(&tport->tp_lock);
+               tty_kref_put(tty);
        }
 
 exit:
 {
        int count, result;
        struct usb_serial_port *port = tport->tp_port;
-       struct tty_struct *tty = port->port.tty;        /* FIXME */
+       struct tty_struct *tty = tty_port_tty_get(&port->port); /* FIXME */
        unsigned long flags;
 
 
 
        spin_lock_irqsave(&tport->tp_lock, flags);
 
-       if (tport->tp_write_urb_in_use) {
-               spin_unlock_irqrestore(&tport->tp_lock, flags);
-               return;
-       }
+       if (tport->tp_write_urb_in_use)
+               goto unlock;
 
        count = ti_buf_get(tport->tp_write_buf,
                                port->write_urb->transfer_buffer,
                                port->bulk_out_size);
 
-       if (count == 0) {
-               spin_unlock_irqrestore(&tport->tp_lock, flags);
-               return;
-       }
+       if (count == 0)
+               goto unlock;
 
        tport->tp_write_urb_in_use = 1;
 
        /* more room in the buffer for new writes, wakeup */
        if (tty)
                tty_wakeup(tty);
+       tty_kref_put(tty);
        wake_up_interruptible(&tport->tp_write_wait);
+       return;
+unlock:
+       spin_unlock_irqrestore(&tport->tp_lock, flags);
+       tty_kref_put(tty);
+       return;
 }
 
 
 }
 
 
-static int ti_set_serial_info(struct ti_port *tport,
+static int ti_set_serial_info(struct tty_struct *tty, struct ti_port *tport,
        struct serial_struct __user *new_arg)
 {
-       struct usb_serial_port *port = tport->tp_port;
        struct serial_struct new_serial;
 
        if (copy_from_user(&new_serial, new_arg, sizeof(new_serial)))
                return -EFAULT;
 
        tport->tp_flags = new_serial.flags & TI_SET_SERIAL_FLAGS;
-       /* FIXME */
-       if (port->port.tty)
-               port->port.tty->low_latency =
-                       (tport->tp_flags & ASYNC_LOW_LATENCY) ? 1 : 0;
+       tty->low_latency = (tport->tp_flags & ASYNC_LOW_LATENCY) ? 1 : 0;
        tport->tp_closing_wait = new_serial.closing_wait;
 
        return 0;
        tport->tp_msr = msr & TI_MSR_MASK;
 
        /* handle CTS flow control */
-       tty = tport->tp_port->port.tty;
+       tty = tty_port_tty_get(&tport->tp_port->port);
        if (tty && C_CRTSCTS(tty)) {
                if (msr & TI_MSR_CTS) {
                        tty->hw_stopped = 0;
                        tty->hw_stopped = 1;
                }
        }
+       tty_kref_put(tty);
 }
 
 
 
        /* set up our port structure making the tty driver
         * remember our port object, and us it */
        tty->driver_data = port;
-       port->port.tty = tty;
+       tty_port_tty_set(&port->port, tty);
 
        if (port->port.count == 1) {
 
 bailout_mutex_unlock:
        port->port.count = 0;
        tty->driver_data = NULL;
-       port->port.tty = NULL;
+       tty_port_tty_set(&port->port, NULL);
        mutex_unlock(&port->mutex);
 bailout_kref_put:
        usb_serial_put(serial);
                port->serial->type->close(tty, port, filp);
 
        if (port->port.count == (port->console? 1 : 0)) {
-               if (port->port.tty) {
-                       if (port->port.tty->driver_data)
-                               port->port.tty->driver_data = NULL;
-                       port->port.tty = NULL;
+               struct tty_struct *tty = tty_port_tty_get(&port->port);
+               if (tty) {
+                       if (tty->driver_data)
+                               tty->driver_data = NULL;
+                       tty_port_tty_set(&port->port, NULL);
                }
        }
 
        if (!port)
                return;
 
-       tty = port->port.tty;
+       tty = tty_port_tty_get(&port->port);
        if (!tty)
                return;
 
        tty_wakeup(tty);
+       tty_kref_put(tty);
 }
 
 static void port_release(struct device *dev)
                port = kzalloc(sizeof(struct usb_serial_port), GFP_KERNEL);
                if (!port)
                        goto probe_error;
+               tty_port_init(&port->port);
                port->serial = serial;
                spin_lock_init(&port->lock);
                mutex_init(&port->mutex);
        for (i = 0; i < serial->num_ports; ++i) {
                port = serial->port[i];
                if (port) {
-                       if (port->port.tty)
-                               tty_hangup(port->port.tty);
+                       struct tty_struct *tty = tty_port_tty_get(&port->port);
+                       if (tty) {
+                               tty_hangup(tty);
+                               tty_kref_put(tty);
+                       }
                        kill_traffic(port);
                }
        }
 
        int status = urb->status;
        struct tty_struct *tty;
        int result;
-       int available_room;
+       int available_room = 0;
 
        dbg("%s - port %d", __func__, port->number);
 
        usb_serial_debug_data(debug, &port->dev, __func__,
                                                urb->actual_length, data);
 
-       tty = port->port.tty;
-       if (tty && urb->actual_length) {
-               available_room = tty_buffer_request_room(tty,
+       if (urb->actual_length) {
+               tty = tty_port_tty_get(&port->port);
+               if (tty) {
+                       available_room = tty_buffer_request_room(tty,
                                                        urb->actual_length);
-               if (available_room) {
-                       tty_insert_flip_string(tty, data, available_room);
-                       tty_flip_buffer_push(tty);
+                       if (available_room) {
+                               tty_insert_flip_string(tty, data,
+                                                       available_room);
+                               tty_flip_buffer_push(tty);
+                       }
+                       tty_kref_put(tty);
                }
                spin_lock(&priv->lock);
                priv->bytes_in += available_room;
 
        struct whiteheat_private *info =
                container_of(work, struct whiteheat_private, rx_work);
        struct usb_serial_port *port = info->port;
-       struct tty_struct *tty = port->port.tty;
+       struct tty_struct *tty = tty_port_tty_get(&port->port);
        struct whiteheat_urb_wrap *wrap;
        struct urb *urb;
        unsigned long flags;
        spin_lock_irqsave(&info->lock, flags);
        if (info->flags & THROTTLED) {
                spin_unlock_irqrestore(&info->lock, flags);
-               return;
+               goto out;
        }
 
        list_for_each_safe(tmp, tmp2, &info->rx_urb_q) {
                                spin_unlock_irqrestore(&info->lock, flags);
                                tty_flip_buffer_push(tty);
                                schedule_work(&info->rx_work);
-                               return;
+                               goto out;
                        }
                        tty_insert_flip_string(tty, urb->transfer_buffer, len);
                        sent += len;
 
        if (sent)
                tty_flip_buffer_push(tty);
+out:
+       tty_kref_put(tty);
 }
 
 
 
 
 struct tty_port {
        struct tty_struct       *tty;           /* Back pointer */
+       spinlock_t              lock;           /* Lock protecting tty field */
        int                     blocked_open;   /* Waiting to open */
        int                     count;          /* Usage count */
        wait_queue_head_t       open_wait;      /* Open waiters */
 extern void tty_port_init(struct tty_port *port);
 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
 extern void tty_port_free_xmit_buf(struct tty_port *port);
+extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
+extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
 
 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
 extern int tty_unregister_ldisc(int disc);